The present invention relates to lasers and, in particular to tunable lasers using a gas or vapor emitter.
Although the scope of the present invention applies generally to the lasing of various dimers of the Group VI elements of the Periodic Table, the experimentation and study on which the invention is based have been directed primarily toward the S.sub.2 dimer. For the most part the following discussion will be with reference to this S.sub.2 study and its results. Applicability to other Group VI dimers subsequently will be discussed. Also, it should be noted that the term `dimer` as presently used, is intended to broadly refer to molecules formed by the union of two simpler molecules. In this sense, it can be considered as including the union of identical molecules such as S.sub.2 and Te.sub.2 as well as the union of non-identical molecules such as TeSe, TeS etc. The term `dimer` thus embraces the more general term `diatomic` which generally applies to heteronuclear molecules.
As has been reported by A. Fowler and W. M. Vaidya, Proc. Royal Soc. A 132, 310 (1931) and G. Lakshminarayana and C. G. Mahajan, J. Quant. Spectrosc. and Radiat. Transfer 16 549 (1976), emission from S.sub.2 (B-X) is widely observed in flames, shock tubes and discharges whenever compounds of sulfur are present. Also, V. S. Zuev, L. D. Mikheev and V. I. Yalovoi, Sov. J. Quant. Electron. 5, 442 (1975) reports an S.sub.2 infra-red laser on .sup.1 .SIGMA..sub.g.sup.+ - .sup.3 .SIGMA..sub.g.sup.- transition at 1.1 mm. The present invention, however, appears to be the first demonstration of lasing based on Group VI dimers including S.sub.2, at allowed transitions from certain excited electronic states to the higher vibrational levels of the ground electronic state. For purposes of this invention a so-called allowed transition is a transition between singlet-singlet, doublet-doublet, triplet-triplet, etc. The infra-red laser of Zuev, et al. is on a relatively weak non-allowed singlet-triplet transition.
Objects of the invention are to provide a tunable laser which is highly efficient, scalable, relatively nondegradable and which offers strong promise for successful pumping by a variety of direct pumping schemes including chemical and electrical pumping.